Gas mask speech transmission



July 14, 1964 v. MOTSINGER 3,140,754

GAS MASK SPEECH TRANSMISSION Original Filed Feb. 12, 1954 INVENTOR.Armard ll. Mofsinger ATTORNEY United States The invention describedherein may be manufactured and used by or for the Government of theUnited States of America for governmental purposes without the paymentto me of any royality thereon.

This is a division of application Serial Number 410,- 056, filedFebruary 12, 1954, now U.S. Patent Number 2,974,665, entitled Gas MaskSpeech Transmission.

This invention relates to a voice transmitting means for gas masks.

In my Patent No. 2,410,454, November 5, 1946, I have shown avoice-transmitting gas mask which includes a vibratable diaphragm ofthin sheet material, such as cellulose film, and a resonating chamberbetween the diaphragm and the mouth of wearer.

An object of this invention is to improve the basic structure shown inmy patent.

A further object of my invention is to provide a voicetransmitting meansfor a gas mask in which the diaphragm is protected against punctures orother injury.

A further object of my invention is to provide an improved resonatorstructure.

FIGURE 1 is a side elevation of my voice-transmitting means. FIGURE 2 isa longitudinal section, on an enlarged scale taken on line 13-13,FIGURE 1. FIGURE 3 is a section on line 1414 of FIGURE 2. FIGURE 4 is aperspective view of an adjusting slide of the device shown in FIGURE 1.

FIGURE 5 is a longitudinal section of a modification, similar to that ofFIGURES 1-4, but without the adjustment means.

In the mask shown in my Patent No. 2,410,454, a resonating chamber wasprovided inside the face-piece, between the diaphragm and the mouth ofthe wearer. In all the modifications of the present invention, aresonating chamber is provided on the exterior side of the diaphragm andis constructed in such a manner that there is no direct opening from theoutside to the diaphragm. The diaphragm is thus protected againstpunctures.

The invention is shown in FIGURES 1 to 4. In this embodiment, diaphragm81 and fixed plates 83 and 85, which are peripherally perforated at 86are crimped in a metal ring 87 which is set in a housing 89 of moldedplastic. The housing is formed by a cylindrical wall 91 and a base 93.Eccentrically mounted in the base is a voice tube 94. In the outer endof the housing is mounted a movable plate 95 centrally perforated at 96.A pair of spring slides 97 of substantially U-shaped form are secured tothe movable plate 95. One leg of the U is fastened to the plate whilethe other leg is slidably mountatent ed in slots 99. The slides are sodimensioned as to exert pressure on the slot walls, thus holding themovable plate in a set position but permitting adjustment when desired.As shown in FIGURE 4, a scale is provided on each of these slides topermit setting the wall to a desired position.

In FIGURE 5, I have shown the simplest form of my transmitter, whichretains the advantages of multiple resonating chambers and a protecteddiaphragm but which does not have the adjustment provided by the otherform. This modification comprises a housing 101 having a cylindricalwall 103 and a base 105. Voice tube 107 is shown as eccentricallymounted in the base. However, when the utmost compactness is desired,this voice tube may be replaced by perforations in the housing base.Mounted within the housing is a diaphragm 109 and fixed plates 111, 113,and 115. The housing 101, voice tube 107, and plates 113 and 115 arepreferably formed of plastic or hardboard and the diaphragm is formed ofseveral, for instance four, sheets of thin material. While celluloseacetate or the other materials mentioned in my patent may be used, Ihave found that superior results are secured by the use of thin sheetsof polyvinylidine chloride such as is sold under the name of Saran.Plate 115 A preferably formed of metal such as aluminum and is crimpedaround the edges of the members as shown at 117 to hold the assemblytogether. Plates 111 and 113 are peripherally perforated at 119 whileplate 115 is centrally perforated at 121.

While I have described specific embodiments in detail, the invention isobviously susceptible to variations. I do not, therefore, desire to belimited except by the scope of the appended claims.

I claim:

1. A voice-transmitting device for gas masks comprising a cup-shapedhousing having a cylindrical wall and a base, at least one aperture forthe entrance of sound waves eccentrically positioned in said base, adiaphragm of thin sheet material extending across said housing joined atits periphery to said cylindrical wall, and spaced from and parallel tosaid base, a perforated plate between and parallel to said base anddiaphragm, a second perforated plate on the other side of, spaced from,and substantially parallel to said diaphragm, a third perforated platebetween and parallel to said second plate and said diaphragm, said firstand third plates being perforated only in their peripheral areas andsaid second plate being perforated only in its central area.

2. A device according to claim 1 wherein a single eccentric aperture isprovided in said base and wherein a tube extends from said aperture.

References Cited in the file of this patent UNITED STATES PATENTS2,466,127 Smith Apr. 5, 1949 FOREIGN PATENTS 572,888 Great Britain Oct.29, 1945

1. A VOICE-TRANSMITTING DEVICE FOR GAS MASKS COMPRISING A CUP-SHAPEDHOUSING HAVING A CYLINDRICAL WALL AND A BASE, AT LEAST ONE APERTURE FORTHE ENTRANCE OF SOUND WAVES ECCENTRICALLY POSITIONED IN SAID BASE, ADIAPHRAGM OF THIN SHEET MATERIAL EXTENDING ACROSS SAID HOUSING JOINED ATITS PERIPHERY TO SAID CYLINDRICAL WALL, AND SPACED FROM AND PARALLEL TOSAID BASE, A PERFORATED PLATE BETWEEN AND PARALLEL TO SAID BASE ANDDIAPHRAGM, A SECOND PERFORATED PLATE ON THE OTHER SIDE OF, SPACED FROM,AND SUBSTANTIALLY PARALLEL TO SAID DIAPHRAGM, A THIRD PERFORATED PLATEBETWEEN AND PARALLEL TO SAID SECOND PLATE AND SAID DIAPHRAGM, SAID FIRSTAND THIRD PLATES BEING PERFORATED ONLY IN THEIR PERIPHERAL AREAS ANDSAID SECOND PLATE BEING PERFORATED ONLY IN ITS CENTRAL AREA.